The present invention relates to a multipole low-voltage circuit breaker having bus bars for connecting contact arrangements of the circuit breaker to one or more circuits, where the bus bars for the input side and the bus bars for the output side are arranged in a row each and both rows are arranged parallel to each other and at right angles to side walls of the circuit breaker.
A circuit breaker of this type has become known, for instance, from European Pat. No. EP-A-0 071 385. There, each terminal is located at a conductor section which extends horizontally backward relative to the customary use position of the circuit breaker. Provision is made by stiffening elements that the bus bars cannot be deformed by current forces.
In this design, the circuit breaker is suited, for instance, for a withdrawable arrangement, in which suitable transition pieces or parts of the break contact arrangement are attached to the bus bars. If, on the other hand, the circuit breaker is to be incorporated fixed into a switching installation, connecting bars are required which are inserted between the terminals of the circuit breaker and the stationary bus bars. It is no problem here to connect the connecting bars to the terminals of the contact arrangement before the circuit breaker is built into the switching installation; if, however, also the connection to the stationary bus bars should be possible without difficulty if the arrangement is not aligned, the length of the connecting bars must not be less than a certain value in order to ensure good accessibility especially from the front of the circuit breaker. Due to the relative length of the connecting bars, the problem arises that the connecting bars are subjected, in the case of a short circuit, to deforming forces which can under some conditions damage not only the connecting bars themselves, but also the terminals and connecting elements.
It would basically be possible to avoid such detrimental deformations by designing the connecting bars as a fixed part of the circuit breaker and by fixing them completely accordingly except for a free end provided for connection to a stationary bus bar. Such a circuit breaker, however, would not be suitable without change also for use as a plug-in circuit breaker. Furthermore, an embedment of the connecting bars would impede the heat removal in an undesirable manner. While on the other hand, a design of the connecting bars with a cross section larger than that required for electrical considerations would increase the strength in the desired manner, the weight and the costs of the connecting arrangement would be increased considerably at the same time, however.